Disorder in the anterior epithelium of cornea can be classified roughly into 4 types, that is, (1) one caused by an inflammation such as infection, (2) hereditary disease, (3) exogenous physical injury and chemical injury caused by chemicals, and (4) nutritional disorder.
Among them, there is a tendency for corneal diseases to increase in recent years due to physical injury accompanied by lacrimal hyposecretion (so-called dry-eye) with the spread of personal computers and contact lens, and those caused by pollinosis, particularly disorder in the anterior epithelium; thus, a drug effective to corneal diseases or disorders in the anterior epithelium of cornea has been demanded.
As drugs recently used in treatment of corneal diseases, artificial tears containing a visco-elastic material such as hyaluronic acid or chondroitin sulfate is known, of which the water-retention effect mainly promotes a cure. There is a limitation, however, in their therapeutic effect, and further it could not be said that they fundamentally cure the corneal disease. A quite new therapeutic agent has been demanded, accordingly.